Telephone supervisory system



Feb. 24, 1931. c. E. LOMAX TELEPHONE SUPERVISORY SYSTEM Filed May 25, 1928 Patented Feb. 24, 1931 UNITED stares PATENT orrics CLARENCE E. LOTIIAX, OF OAK PARK, ILLINOIS, ASSIGNOR TO RESERVE HOLDING CQMTPANY, OF KANSAS CITY, MISSOURI, A. CORPORATION OF DELAWARE TELEPHONE SUPERVISORY SYSTEM Application filed May 25,

maintenance.

c sending an attendant out to correct it.

All the maintenance in these small exchanges isusually taken care of from the distant main exchange, and formerly an op erator at the main exchange, at specified time intervals, dialled a special number which automatically connected her with the alarm system of the branch exchange. In systems ot'this kind. the alarm signals such as lamps, huzzers, and bells. which are operated when ever an abnormal condition occurs that requires a tention, remain in operated condition until the trouble has been corrected or until the distant operator ascertains this c011- dition by dialling the branch exchange and continuedoperation of the alarm signals, before an abnormal condition is corrected causes needless consumption of current, which in a branch exchange where a small battery is usually installed, may at times be quite serious. In some other cases separate alarm leads to the main exchange are provided for giving the alarms, but if the distance istoo great this arrangement is objectional.

The object of this invention, therefore is the provision of means for economizing on battery current consumption in unattended branch exchanges by arranging the alarm signal circuits in such a manner that they will not become operated until a time when an attendant is present and can correct the abnormal condition indicated by the alarm signals.

A feature of the invention is the means whereby the distant exchange operator can dial a special number in the branch exchange and, by receiving a tone over the trunk, be informed that the branch exchange is operating satisfactorily, and if no tone is received, an indication that some abnormal condition exists in the exchange which requires immedi- The l 1928. Serial No. 280333.

ate attention, whereupon an attendant is clospatched to the branch exchange to immediately correct, it.

A further feature of the invention resides in the provision of a special key and suitable circuit arrangements at the branch exchange whereby the various alarm signals are brought into operation only at a time when the attendant can attend to the abnormal con dition indicated, and correct it.

Another feature resides in a new and improved voltage regulating arrangement for an unattended branch exchange, comprising a high voltage relay arranged to control both the starting and stoppingol the charging of the battery, that relay being energized to stop the charge when the voltage or the battery reaches a predetermined high limit. However, instead of depending on the rather uncertain low voltage release of a relay, the circuit of the high voltage relay is opened at the end of each call througl i the exchange, that relay falling back to retestthe voltage and start the charge so that the battery is immediately charged up to the maximum voltage.

There are other features not specifically mentioned, but which will become apparent by a perusal of the following detailed description which, together with the single sheet of drawings, constitutes a preferred embodiment of the invention.

Referring now to the drawing, the apparatus shown therein will be briefly described. The apparatus is all shown as being in its normal operating state. The power board in the upper portion of the drawing contains the batteries 11 and 12 which supply current to the bus bars 13 and 14; and are in turn sup plied with charging current through the rectiiier 7 from the A. C. current power supply. The rectifier '4' of the well-known two-elementvacuum tube type, the filament of the bulb. being supplied with lighting current from the upper right-hand portion winding of the transformer 6.

The keyK is a locking key that completes the circuits to the various alarm lamps in the lamp panel in conjunction with various relays, when it is operated by an attendant.

"arrangement 1 (not shown).

. In the lower portion of the drawing the reference characters L7, l8, and 49 indicate a set of Wipers of a connector switch, which under control of the distant operator are adapted to come into engagement with a set of bank contacts 50, 51, and 52 in well-known manner. The other bank contacts of this switch lead to varioussubscribers lines in the branch exchange. This type of switch is well known in the art, and it is not thought necessary to go into a detailed explanation of its operation. i

The ringing interrupter machine 65 is operated I each time a call originates in the branch exchange, and operates its shaft to rotate switch arm 68 through a suitable gear The ringing generator'80 is also mounted on this shaft. A. further explanation of the operation will be given later on. I

Separate batteries and ground connections are shown in the drawing on all the apparatus, in order to make the drawing clearer,

but it must be understood'that these are all connected to the bus-bars 13 and 14, as indicated by the arrow-headed leads thereon.

The normal state of the apparatus is as shown in'the drawings, with the marginal high voltage relay 32 energized, holding relay 31 energized. The arrangementis such that each time a call is made in the exchange the charge is started for the batteries. This takes place each time the relay 33 is energized momentarily due to the release of a call in the exchange, as will be fully explained hereinafter. Upon the energization of relay 33, the circuit of the marginal high voltage relay 32 is opened. 3 Relay 32 falls back and opens the circuit of the slow-acting relay 31. Relay 31 in turn. closes, at its upper contact, a circuit for the heavy duty relay 5, whereupon relay 5 energizes and applies the commercial power to the left-hand winding of the transformer 6, causing the rectifying tube 7 to li 'ht up and start to charge the battery. The charging currentto the battery passes through resistance 8' around which relay 9 is shunted. As a result of this, relay, 9 operates and opens the circuit of relay 23 before relay 23 can, operate responsive to the closure of its circuit at the inner armature of the slow charge-starting relay 31. The charging current is delivered first to battery 11, and this battery receives the pulsating current just as it is rectified. Between the battery 11 and the battery 12, there is an impedance 10, which smoothes out the current flow and enables the potential of battery 12 to remain constant.

Although the circuit of thema-rginal relay 32 was only momentarily opened by relay 33, it will not pull up when its circuit is closed againdue to its marginal adjustment. It will only pull up when the critical predetermined voltage of the battery is reached, at which time the charge 18 cut off.

When the voltage reaches the required predetermined amount, which time may be after a long or short time interval depending upon Ithedrain on the battery, due to the operation of the switches in the exchange, the marginalv l'iigh-voltage relay 32 reoperates and closes the circuit of relay 31. Relay 31 reoperates' and opens the circuit of relay 5, at the same time opening, at its upper contacts,

another point in the circuit of relay 23. Re-

branch exchange and then manipulate her calling device in accordance with -a special number to set the wipers 47-, 4:8, and49 of the connector switch onto the bank contacts 50, 51, and 52. Ground'potential is now fed tirough wiper 47, bank contact 50 tl1rough relay 28 to battery. Relay 28 energizes and closes its weighted armature onto the make contact after a slight interval and energizes relay 29. This slight;.time interval before relay 29 pulls up its lower suflicient time for the circuit of the ring-cutoff relay of the connector switch to become energized and cut off the ringing current in the connector, as is well known. Whenrelay 29 becomes energized, a circuit is com-. pleted from the ringing generator 80, lower contacts of relay 26, small tone condenser 81, lower closed contacts of relay 29, through bank contact 52 and wiper l9 and over the trunk to the operators head set. The oper-;.

ator will thereby hear a distinctive tone in her headset which indicates to her that all the apparatus, including the ringing machine at the branch exchange, is operating in a satisfactory manner.

Assume newt-hat some abnormal condition existed at the branch exchange prior to or at the time the operator makes her periodic call. In this event, the relay 26 wouldbe energized, as will be explained hereinafter, and this relay will open its lowermost contacts to disconnect the generator 80 from the circuit through bank contact 52. Then the operator makes her call, she will not receive any tone in her headset and she will thereby know that an emergency condition exists at the branch exchange requiring immediate correction. She immediately dispatches an attendant to the branch exchange who will perform as his first act the operation of the key armature allows Failure of switch to release 3 Each time a switch in the exchange releases, the series supervisory relay 36 energlzes due to the fact that current for the release magnet of the switch s supphed through this relay. Ordinary relay 36 operates only momentarily and falls back again as soon as the release operation has been com pleted. When relay 36 operates, it connects ground from its upper contacts through the lamp 41, to conductor 75 and through the low wound relay 33 to battery. Relay 33 operates and opens the circuit of the high-voltage relay 3 2, which, upon falling back, opens the circuit of relay 31. When the relay 31 falls back-and closes its contacts, the circuit for the charging control relay 5 is closed and the rectifier 7 beginsto charge the batteries. Relay-33 in addition to opening the circuit of the l1lgl1-V0ltd 6 relay 32 also closes ground on conductor $0 to the ringing interrupter machine 65. This machine which is also op.-

erated each time the interruptenstart conductor INT. ST. is grounded by the opera tion of a switch in the exchange has mounted on its shaft the ringing machine 80. which feeds ringing current to all the switches In addition, the machine has a number of cams mounted on. its shaft ,for the purpose of interrupting the ringing current. One such cam 68. is shown, and this places ground first on the pickup conductor which may be used to start the ringing and subsequently, when the arm travels around, ground on the stop. conductor which may be used to stop the ringing. In addition, this cam feeds ground first to conductor 67 and then to conductor 66. l

It may happen occasionally that a switch does not release properly for some cause, and the release magnet circuit, therefore, remains closed for an undue length of time. In this case, relay 36 remains operated long enough for an alarm to be brought in, as will now be explained.

In case relay 36 remained operated for an undue length of time, ground is placed on conductor 7 5 through lamp 4:1 and also to the ringing machine 65. The cam 68 will then place ground on conductor 67 and energize relay through contacts 63 of the opererated key K. Relay 35 energizes and locks up throughits lower. contacts to the grounded conductor 75. If relay 36 should fall back before the cam 68 has grounded conductor 66, relay 35 falls back and relay 3a is not operated. However, if relay 36 remains operated, relay ol is operated through the upper contact-s ofrelay 35 from the stop conductor 66. Relay 34llocks itself up through its lower winding in parallel with the lower winding of relay 35 to conductor 75. The lower winding of relay is of relatively high resistance, and thelamp all does not light through this lower winding. The lower winding of relay. 3%, however, is of relatively low resistance, and the lamp 41 now becomes permanently lighted. Relay Stat its upper contacts closes a circuit for relay 26 which, upon energizing, disconnects the generator 80, so that the operator, upon calling into the exchange, will be aware that an abnormal condition exists. At its innermostcontacts relay 26 closes the circuit for the buzzer 21 to call the attendants attention to the trouble, which is inaddition to the lighting of the lamp 41. The attendant repairs the switch which had failed to release and then restores the key K to normal. The release of relay 36 restores all the circuits again to their normal condition. Should the operator call and energize relays 23 and 29, as has been explained, before the attendant operates the key K, the relays and 35 would not be operated, but the ground on conductor will energize relay 30. through the closed inner contacts of relay 29. llelay 30 operates its contacts to close the circuit of relay 26, whcreuponthe tone generator is cut off and the operator is appraised that an abnormal condition exists by not receiving a tone.

Fuse blown In case a fuse, blows in the exchange, the spring contacts on the fuse will make contact, in the wcll-known manner, with the fuse bar that is just below the main bus-bar 13, thereby closing a circuit for the fuse alarm lamp 1 8, from battery on the blown fuse, through lamp 38, low wound relay 27, to ground at springs 62 of the operated hey K. Relay 27 energizes and closes the circuit of relay 26 which pulls up and cuts oil the generator 80 and in addition closes the circuit to the buzzer 21.

Should the operator have called the ex change afterthe fuse was blown and before the key K was operated, the relays 28 and 29 would thereupon become operated, as has been explained, andin addition relay 29 would place ground at its upper contacts through relay 27 and through the lamp 38 to battery at the blown fuse. Relay 27 closes its contacts and operates relay 26, which in turn cuts off the generator 80, indicating to the operator that a case of trouble exists. Relay 26 also. closes at itsinner contactsthe circuit for the buzzer 21 to call the attention of the attendant to the lighted fuse lamp 38.

Fail me of charging oz'rcm't case the charge tails t-o' start. This may be due to a allure on the part of the commercial power or in the rectifier 7, or-possibly in the contacts of relay 5, or the transformer 6 may be burned out. At any rate, it the charge fails to start,relay 9 does not operateand the circuit for relay 23 is closed through the inner contacts of relay 31. WVhen relay 23-ope ra'tes, atter'ia slight interval, it closes a circuit for relay 24 whereupon relay 24 operates and,

after a slight interval, closes a circuit from battery, at its upper contacts, to the charge alarm lamp 37 and relay 27 in series to ground on springs 62 of the key K, which is assumed to bein operated position. It the key K were not operated and the operator called into the exchange, relays 28 and 29 would be energized and at its upper contacts relay 29 would energizerelay 27 and light the lamp 37, but in this case the lamp 37 would only be lit while the operator was listening in. Relay 27 in this case, would close the circuit to relay 26 to cut oil the generator 80, informing the operator ofa case of trouble at the exchange. The at tendant notes the lighted condition of lamp 37 and in addition the buzzer .21 operates from the inner contacts of relay 26 to call his attention to the fact that the charging circuit has failed.

M. D. F. alarm The M. D. F. alarm consists of the so-called -Fheat coils 41 associated with each line in the exchange, and in case of trouble outside the exchange in the line, these heat coils 41 become fused and a ground is placed on the associated common conductor, closing a' circuit to battery through the alarm lamp 39,

spring 61 of the operated key K, and thence .to relay 25. Relay 25, upon operating, closes the circuit to the buzzer to call the attendants attention to the lighted lamp 39. It will be noted that in connection with this alarm the relay 26 will not be energized to cut ofl' the generator 80, when the operator calls in. It

is not necessary for the operator to be aware 1 of an M. D. F. alarm, as only one line will be effected in the exchange, all the other equipment being in operative condition.

Subscriber fails to hang up The conductor 69 leads to a release supervisory relay which feeds battery potential to a relay in a switch each time a call originates condition by thelighting of the lamp 40 and b well-known means suchas as l in" a .V 9 1P 1 g howler tone to the line, attract the subscribers attention to it, and request him to replace his receiver on the hook.

Fail-are 0; ranging generator 1n the event that the ringing generator fails to function, due to the inoperativeness of the interrupter machine 65 or some other cause, the operator, upon makingher periodic call into the exchange, will energize relays 28 and 29, but she will receive no tone and thereby will knowthat something is wrong at the exchange and dispatch the attendant to connect it. 11 no trouble is apparent when the attendant operates the key K, by no lamps lighting up he will know that the generator or ringing machine is not operating properly. 7

Vfhile the exact nature of any of the above described abnormal conditions at the branch exchange cannot be determined by the operator at the distant exchange, she will only know, by not receiving a tone in her headset, that some trouble exists. Therefore, as she cannot remedy the trouble herself from the main exchange, it is only necessary for her to know that it exists, and the attendant will be promptly despatched to the branch exchange in any case to remedy the trouble. The operation of the key K discloses the exact nature of the trouble to him.

It will thus be seen that a novel supervisory system for an unattended branch exchange has been designed whereby the trouble alarms do not function and put an unnecessary drain upon the batteryuntil such time as the distant operator has become aware of the condition and has despatched an attendant to the branch exchange who will operate a key to render all alarm signals operative. This system utilizes a minimum amount of equipment for'pertorming a large number of different operations of the alarm signals in an economical and eliicient manner in any kind of unattended branch exchange,

What is considered new and is desired to have protected by Letters Patent is'pointed out in the appendedclaims:

,1. A battery supply system comprising a main and an auxiliary battery, charging equipment for charging said auxiliary battery, circuit connections through which said auxiliary battery charges said main battery, a marginal relay, a circuit for said relay including contacts which are intermittently opened, said relay being connected to said batteries when said contacts are closed and arranged to operate when the voltage across said main battery. reaches a predetermined value, and means controlled by said relay to govern the charging of said battery.

I 2. A batterysupply system for telephone exchanges comprising a main and auxiliary battery, charging equipment for charging said auxiliary battery, circuit connections a through which said auxiliary battery charges said mainbattery, a marginal relay, a supcn visor-y relay operated each time a call is terminated, and a circuit for said marginal relay including contacts on said supervisory relay and connections to said batteries, said marginal relay arranged 'to operate and cut oil said charging equipment when the voltage across saic main battery reaches a prede termined value or when said supervisory relay is operated.

3. A battery supply system for a telephone exchange comprising a main and auxiliary battery, charging equipment for charging said auxiliary battery, means whereby said main battery ischarged from said auxiliary battery, a marginal relay controlling said charging equipment, a supervisory relay operated each time a call in the exchange is terminated, a circuit for said marginal relay including contacts on said supervisory relay and connections to said batteries, said margina-l relay arranged to control said charging equipment when the voltage across said batteries reaches a predetermined value or when said supervisory relay operates to control said contacts in said marginal relay circuit.

4. In combination with a battery and charging equipment therefor and a power relay controlling the charging equipment, a marginal relay controlling the circuit of said power relay and arranged to operate when the battery reaches a predetermined high: value, and intermittently opened contacts for connecting said marginal relay to said battery for controlling the charging of said battery. 7

5. In a' telephone exchange, a battery, charging equipment for charging said battery, a marginal relay connected to said battery and controlling said charging equip ment, a supervisory relay operated each time a call is terminated in the excliange, a circuit for said marginal relay including contacts on said supervisory relay and connections to said battery, said marginal relay arranged to control said charging equipment when the voltage across said battery reaches a predetermined value or when said supervisory relay operates to control said contacts in said marginal relay circuit.

6. In a telephone system,a battery, charging eqmpment for charging said battery, a

marginal relay .connected to said battery through a circuit including contacts which are intermittently opened, said relay being connected to said battery when said contacts are closed and arranged to operate when the voltage across said battery reaches a predetermined value, and means controlled by said relay and said contacts to govern the charging ofsaid battery.

7. In a battery supply system, a battery,

charging equipment for charging said battery, a power lead for supplying current to said charging equipment, amarginal relay normally connected to said battery through intermittently operated contacts, a power relay controlled by saidmarginal relay controlling the circuit otsaid power lead, and means controlled by said marginal relay and said contacts to govern the charging of said battery. l

8. In combination with a storage battery, a discharge lead, a power supply lead over which power is supplied for charging the battery, a voltage marginal relay normally bridged across the battery, a relay connected in series with said discharge lead and responsive to current flow thereover,andmeans including contacts on both relays for controlling the tlow of current in said power lead.

9. In acurrent supply system wherein a storage battery supplies current to a current consuming device and in which a current source is provided to charge said battery, an electromagnetic device controlled in accord ance with the state of charge of said battery for stopping the charge, and means responsiverto said current consuming device being connected to said battery for removing said electromagnetic device from under the control of said battery.

10. Ina battery charging system wherein the discharge current from the battery to be disconnecting said charge a predetermined time after said discharge current ceases.

12. In a battery charging system wherein the discharge current from the battery to be charged flows intermittently, automatic means responsive to a flow of discharge current from said battery for starting the charge for the battery, and means for automatically disconnecting said charge after said discharge current ceases and said battery reaches a predetermined state of charge.

13. In a battery charging system wherein the discharge current from the battery flows i.

intermittently, means responsive to a flow of discharge current fromsaidbattery for automatically starting the charging apparatus to charge said battery, and means responsive to the potential of the battery reaching a predetermined'point after said discharge current ceases for disconnecting said charging apparatus. i

.14. In a telephone exchange, a battery, charging equipment for charging said battery,*a power relay forcontroiling said charging equipment, a marginal relay connected to said battery and controlling said powerrelay,

a supervisory relay operated each time in re-' sponse to the termination of a telephone connection in said exchange, contacts on said supervisory relay controlling the connection of said'marginal relay With said battery, and

means responsive to a predetermined voltage of said battery.

on said battery or the operation of said contacts by-said supervisory relay for operating said marginal relay to control the charging 15. In a telephone exchange, a battery, charging equipment for charging said. battery, a power relay controlling the application of said charging equipment with said battery, a supervisory" relay operated responsive to the termination of each call in said exchange, a' marginal relay controlling said power relay, contacts controlled by said supervisory relay normally connecting said marginal relay With said battery, and means responsive to a predetermined voltage of said battery in one instance and the operation of said contacts by said supervisory relay in another instance for operating said marginal relay to control the charging of said battery.

In Witness whereof, I hereunto subscribe my-namethis 22d day of May, A. D. 1928.

j CLARENCE E. LOMAX. 

